Abstract
A novel potentiometric 8-hydroxyquinoline PVC coated graphite sensor incorporating 8-hydroxyquinoline (oxine)-tetraphenylborate (TPB) ion pair as an electroactive material and dioctylphthalate (DOP) as a solvent mediator is described and electrochemically evaluated. The proposed sensor exhibits fast Nernstian response for 8-hydroxyquinoline over the concentration range 10
−6
-10
−1
mol L
−1
with a cationic calibration slope of 59.0 ± 0.5 mV/concentration decade and a detection limit of 4 × 10
−7
mol L
−1
(0.05 ppm). Interferences from common inorganic cations are negligible. The sensor is successfully used for monitoring titration of some metal ions (e.g., Cu
2+
,
, Cd
2+
, Ca
2+
,
, Co
2+
, Ni
2+
, Zn
2+
, Th
4+
, and Pb
2+
) with 8-hydroxyquinoline titrant at suitable pH values. Some metal ions (e.g., Cu
2+
) are determined in presence of many common metal ions without interference. The average recoveries of the tested metal ions ranged from 95-98 ± 1% and a mean standard deviation is 1.8%.